GB820820A - Method and apparatus for the heating of industrial furnaces - Google Patents

Abstract

820,820. Burners. UNION CARBIDE CORPORATION. April 27, 1957, No. 13490/57. Class 75(1) The invention consists in a method of and apparatus for heating an industrial furnace, the method comprising burning a mixture of fluid fuel and an oxidant, such as oxygen or air, in a combustion zone, discharging the combustion products at a velocity greater than 0.5 Mach number into a preheating and atomizing zone supplied with a stream of fluid fuel and discharging the resulting preheated and atomized mixture into the furnace (not shown) to burn therein with air; the apparatus comprising a burner having an elongated body 10 provided with a longitudinal passage 12, Fig. 2a, forming an internal combustion zone 38 and an internal preheating and atomizing zone 72, Fig. 2b, means for feeding and burning a stream of combustible mixture in the combustion zone 38, means for conveying the products of combustion at a velocity greater than 0.5 Mach number into the atomizing zone 72, means for supplying a stream of fluid fuel to the atomizing zone 72 at substantially 90 degrees to the flow path of the combustion products, and means for discharging the stream from the atomizing zone 72 into the furnace. The combustible mixture supplied to the combustion zone 38, Fig. 3, is ignited by a pilot burner 14 having a combustion chamber 22 discharging through a passage 36 into the combustion zone 38. The pilot burner 14 has a fuel inlet conduit 16, communicating with a conduit 18 which passes fuel through a radial metering port to the pilot burner combustion chamber 22. A pilot burner oxygen conduit 30 communicates with a passage 32 which discharges through a radial metering passage to the combustion chamber 22. The pilot burner is cooled by water which flows from an inlet 56, Fig. 2a, at the rear of the burner forwardly to -annular passages 48, 50 at the front of the burner and then rearwardly to a water outlet 42. A thermocouple 26 is inserted in the pilot burner. The oxidant supplied to the combustion zone 38 enters the burner through a radial conduit 60, Fig. 2a, and then passes along an annular passage 62 between the pilot burner 14 and the longitudinal burner passage 12. The fuel to the combustion zone 38 enters the burner through a radial conduit 64, passes through a plurality of radial metering ports 68 and discharges into a shallow annular mixing passage 70 communicating with the annular oxidant passage 62 and discharging into the combustion zone 38. The fuel and oxidant are preferably fed to the combustion zone 38 in proportions to form a stoichiometric mixture. The fuel to be atomized is introduced through a radial conduit 74, Fig. 2b, and passes through two borings 76 to tangential inlets in spray nozzles 78 having ports 84 discharging into the atomizing zone 72. The mixture of combustion products and sprayed fuel is carried along the atomizing zone 72 and is discharged from the open end 86 thereof into the furnace. Cooling water enters the burner through conduit 88, Fig. 2a, passes through passages 92 to an annular passage 94 supplying a plurality of compartments 96 surrounding the combustion zone 38; it then passes through a passage 100, Fig. 2b, to a plurality of compartments 102 surrounding the lower half of the atomizing zone 72 and then returns through a further plurality of compartments 102 surrounding the upper half of the atomizing zone 72 to a passage 104 and thence to an outlet conduit 106. Two burners as described are mounted at opposite ends of an open hearth furnace and are supplied continuously with fuel, oxidant and cooling water for the pilot burners and alternately with fuel and oxidant for the' combustion zone 38 and with fuel to be atomized.